There is a need for a noni-contaminiating, high pressure ratio compressor for use in miniature J-T crycoolers, which potentially offer excellent devices for sensor cooling applications in space. A weak link in present J-T coolers is the compressor, which should produce high pressure ratios of 10-30, and operate reliably over extended periods. Also, the working compressor fluid must remain ultra-clean, while commercially available high pressure ratio compressors are typically oil flooded, and require extensive cleanup of the gas stream. Although sorption compressors may provide a source of clean high pressure gas for space J-T coolers, they have relatively low efficiencies and high mass. Additionally, in sensor cooling applications, the mass flow working fluid rates could be very small, thus calling for miniaturization of the compressor components,